1. Field of the Invention
The present invention relates to communication networks. More particularly, the present invention relates to the use of blade servers in communication networks, including but not limited to Fiber Channel (“FC”) networks.
2. Description of the Related Art
A recent trend in the data center is to deploy blade servers. Blade servers generally have a modular chassis and a set of central processing unit (“CPU”) blades plugged into that chassis. In addition to CPU blades, there are typically 2 or more network interface blades. Some of these network interface blades are used for FC connectivity, generally to a storage area network (“SAN”), and some of them are for Ethernet connectivity. The benefits of blade servers include greater rack density, simplified interconnect, and lower cost.
The deployment of a typical blade server is illustrated in FIG. 1. Blade server 105 includes blades 110, each of which is interconnected with each of switches 115, 120, 125 and 130, all within a single chassis 135. To other devices in network 100 (e.g., to host device 142), each of blades 110 may appear to be an individual device. Each of blades 110 may provide, for example, the functionality of a server that is operating independently of the other blades 110 within chassis 135.
In this example, Ethernet switches 115 and 120 provide redundant connections with enterprise network 140 and Internet 145. FC switches 125 and 130 provide redundant connections with SAN 150 and storage devices 155. Blade servers 106, 107 and 108 are similarly configured.
As shown in FIG. 1, blade servers configured for communication with a SAN normally include two FC switches. FC networks can support a limited number of total switches, which is normally a maximum of 239. Some popular switch implementations have even more severe restrictions on the number of switches in the SAN, e.g., a maximum of 32 switches. These maximum numbers include core switches, edge switches and FC switches within blade servers. It can readily be seen that such limitations are causing data centers to quickly reach the total FC switch scaling limit.
In addition to the foregoing issues, including additional switches creates additional administrative overhead. Often information technology (“IT”) departments are organized such that those that administer the SAN are not the same people that administer the servers. The server administrators may not have the skills necessary to administer the SAN and vice versa.
With the blade server architecture, since switches and servers are in the same chassis, this division of responsibility is difficult to maintain. Generally, the server administrator takes responsibility for the blade server, including the switch embedded inside it. However, if the server administrator lacks sufficient expertise for SAN management, the server administrator may do something to a blade server switch that will adversely affect the rest of the SAN.
Even if a network administrator is competent to administer both a SAN and servers, the number of additional FC switches introduced by blade servers in a network creates an administrative burden. Normally, the only switches that a SAN administrator will manage are those of the switch fabric. However, with prior art blade servers attached to the SAN, each FC switch of every blade server has its own parameters that must be managed. From a management perspective, this effectively extends the switch fabric that must be managed to the switches in the blade servers.
Moreover, if an FC switch in a blade server can only be configured for a fabric of, e.g., 32 switches, this minimum will apply to the entire fabric even if the core and edge switches could be configured for a fabric of, e.g., 239 switches. In other words, the switch having the lowest maximum will control the maximum number of switches that can be included in the fabric.
It would be desirable to address at least some of the foregoing limitations of the prior art.